1. Disable your XP firewall. (Norton & XP firewalls WILL clash when used together & give unreliable results & less security, not more.)
2. Configure your Norton Firewall to allow LW full access; Configuring Norton Internet Security
3. Linksys WRT54G is a 'lemon' version Linksys released. At least their firmware has major problems & they never bothered to fix it. It is thus unreliable when using with heavy net programs & will drop connections when used in UPnP mode. It is more reliable when port forwarded. There is a 3rd party fix to the firmware but I don't recommend it to anybody who is not sure what they are doing, else you could render the device unusable. To learn more about that, see WRT54 listing under the UPnP section here Connection problems? Check here first! (click on link)